Pneumatic rubber tires have been prepared which contain innerliner layers to promote, or retard, resistance to air permeation and have also been prepared which contain a puncture sealant layer.
While, historically, pneumatic tire innerliner layers are often comprised of elastomer(s) which are resistant to air permeation, such as for example butyl and halobutyl rubber, alternative materials are sometimes sought for pneumatic tire innerliner layers.
For example, pneumatic rubber tires have been proposed which contain an air permeation resistant film, or thin layer as a tire innerliner to promote resistance to a somewhat gradual leakage, or permeation, of air contained in the pneumatic tire cavity through and into various rubber components of the tire. Such proposed films may be comprised of, for example, a resin such as a thermoplastic resin which contains a dispersion of elastomeric domains, or particles. For example, see U.S. Pat. Nos. 7,730,919, 7,798,188, 7,905,978, 7,954, 528, 7,976,666 and 8,021,730 and Patent Application Serial Nos. 2008/0047646 and 2009/0038727.
Other candidates for such films have been proposed which are indicated as having a relatively low permeability to air or oxygen including, for example, polyvinylidene chloride, nylon and polyester. See, for example, U.S. Pat. Nos. 5,040,583 and 4,928,741. Composites containing such film have been proposed comprised of, for example, at least one layer of such film of non-elastomeric material sandwiched between two elastomeric layers of elastomeric compositions.
Various of such films may be also be suitable to promote a degree of physical resistance to tire puncturing objects. However, in general, if such films are positioned on a firm, solid, rubber layer of the tire, their ability to resist penetration by sharp objects (e.g. a nail) pushing from the outside of the tire through its carcass, without unnecessarily fracturing the film is challenged.
In practice, pneumatic rubber tires have also been proposed which contain sealant layers to promote sealing against tire puncturing objects, such as for example a nail, and to promote filling a hole by the sealant which might have been left by the puncturing object such as a nail to thereby maintain a degree of integrity of the surface of the pneumatic tire cavity and to resist air leakage from the tire to the atmosphere. For example, see U.S. Pat. Nos. 6,962,181, 6,840,295, 6,837,287, 4,895,610, 4,228,839, 4,171,237, 4,140,167, 3,048,509, 2,877,819 and 1,239,291.
Additional pneumatic tires have been proposed which contain composites of one or more layers which might promote puncture sealant and penetration resistance. For example, see U.S. Pat. Nos. 6,159,613, 6,148,885, 6,011,093 and 6,840,295, U.S. Patent Application Serial Nos. 2011/0056604, 2010/0294411, 2010/0175804 and 2010/0263778 and PCT Patent Application No. WO2011/012699.
For this invention, it is proposed to provide a pneumatic rubber tire with a composite comprised of a layered combination of puncture sealant layer and protective air permeation resistant film. In this manner it is envisioned that the relatively soft puncture sealing layer may provide an appropriate backing for the protective film to promote a resistance to its rupturing caused by a penetrating object such as a nail while the layered composite itself promotes a puncture sealing effect for the pneumatic tire.
Accordingly, it is an undertaking of this invention to evaluate providing a beneficial layered composite of sealant and protective film for a pneumatic tire innerliner.
In the description of this invention, the term “phr” is used to designate parts by weight of an ingredient per 100 parts of elastomer unless otherwise indicated. The terms “elastomer” and “rubber” are used interchangeably unless otherwise indicated. The terms “cure” and “vulcanize” are used interchangeably unless otherwise indicated.